Modeling Growth of Newly Formed Particles and Cloud Condensation Nuclei Production in an Urban Environment

RAHUL ZAVERI (1), Richard Easter (1), Nicole Riemer (2), Matthew West (2), Kelley Barsanti (3), Chongai Kuang (4), James Smith (5), Peter McMurry (6)

(1) Pacific Northwest National Laboratory, Richland, (2) University of Illinois, Urbana-Champaign, (3) Portland State University, Portland, (4) Brookhaven National Laboratory, Upton, (5) NCAR, Boulder, (6) University of Minnesota, Minneapolis

     Abstract Number: 749
     Last modified: May 14, 2010

Abstract
Modeling growth of newly formed particles and their eventual contribution to CCN population is a challenging problem. Sources of uncertainties and errors in model predictions include: a) incomplete understanding of the various growth processes and knowledge gaps in the fundamental chemical and physical properties of aerosols, and b) various assumptions and numerical simplifications that are typically made in sectional and modal aerosol models for computational efficiency.

Here, we apply the recently developed stochastic particle-resolved aerosol box model PartMC-MOSAIC (Zaveri et al. 2008, JGR; Riemer et al., 2009, JGR) that rigorously simulates the evolution of aerosol size, composition, mixing state, and the associated cloud condensation nuclei (CCN) activation properties in an idealized urban plume. New particle formation was simulated in PartMC-MOSAIC with the power law model of Kuang et al. (2008). The model explicitly resolved the size and composition of individual particles from a number of sources and tracked their evolution due to condensation, evaporation, coagulation, emission, and dilution over a period of multiple days. The paper will present results on the potential roles of competitive gas-particle partitioning of ammonia, nitric acid, sulfuric acid, and organics over the entire aerosol size distribution in the growth of freshly nucleated sulfuric acid particles to sizes that are large enough to serve as CCN (e.g., dry diameter >100 nm). The effects of coagulation and dilution will also be discussed.

References
Kuang, C. et al. (2008), Dependence of nucleation rates on sulfuric acid vapor concentration in diverse atmospheric locations, J. Geophys. Res., 113, D10209, doi:10.1029/2007JD009253.

Riemer, N. et al. (2009), Simulating the evolution of soot mixing state with a particle-resolved aerosol model, J. Geophys. Res., 114, D09202, doi:10.1029/2008JD011073.

Zaveri, R. A. et al. (2008), Model for Simulating Aerosol Interactions and Chemistry (MOSAIC), J. Geophys. Res., 113, D13204, doi:10.1029/2007JD008782.